Machine-switching telephone-exchange system



L. POLINKOWSKY. MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED AUG.27| 1918.

1 $372,448. Patented Mar. 22, 1921.

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L. POLINKOWSKY.

MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED AUG.27, 1918.

Patented Mar. 22, 1921.

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L. POLINKOWSKY.

MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.'

' APPLICATION FILED AUG.2Z, 191B. 1 72,448. Pa nted Mar. 22, 1921.

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L. POLINKOWSKY.

MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED Aue.21. 1918.

1,372,448. Patented Mar. 22, 1921,

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by Affy.

I' POLINKOWSKY.

MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED AUG.27, I918. I

Patented Mar. 22, 1921.

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MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

L. POLINKOWSKY.

APPLICATION FILED AUG.27- I918.

vPatented. Mar. 22, 1921.

7 SHEETS-SHEET 7,

3 UNITED STATESPATENT OFFICE.

LIPA roLINKow'sKY, orrrvnn PARK, LONDON, ENGLAND, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCOBPOBKTEED, OF NEW YORK, N. Y.,

NEWYORKI To eZZ w/wmz't may concern:

Be it known thatl, LIJPA Pomnnowsnr, a citizen of Russia, residing at 70 WVes'tbourne Terrace, Hyde Park, London, (.5 England,

have invented certain new and "useful Improvements in Machine-Switching Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description. l 1 a 1 a y This invention relates to machine switch ing telephone exchange systems and more particularly to machine switching telephone systems wherein callsare to be extended by an A operator at a manual common tery exchange to subscribers over a semiautomatic B board. y A particular feature provides that apportioning means is brought into, action Wl 1ich automatically brings the selection initiated on the B boardunder the control of the plug inserted in the jack of the Afjboard,

and also provides thatthe connection is automatically released on Withdrawing the plug-from the jack on the outgcmg end oi the trunk line.

In systems of the above character-the Bil operators position is providedvvith] a set of number keys, which the operator depresses according' to the designation of the Wanted number, register sets which itake positions corresponding to the depressednuinber keys and assignment keys individual to, thetrunk lines whereby the, depression" of an assign-h inent hey causes theautornatic connectionlot the incoming end of thetrunk line with rree register set The FB operator after receiving" from the uh operator over an order Wire the number of the Wanted sub:

scriber has in a regular connection only to depress the assignment lreyota free trunk line give the; A71 operator the number of such trunk line and depress the number keys.

A further feature or the invention there fore provides thatfthe selection is initiated on the P board and is partially progressed.

disregarding ivhether lthe plug has been brought into the jack onthe- A board or not, but the completion of the selection is made automatically, dependent upon the insertion of the pluginto thej ack on the out going end of the trunk line. i f in the operation of systems of the above character it is desirable that the semi-automatic B operator be able torestorethe has MACHINE-SWITCHING: TELEPHONE-EXCHANGE SYSTEM.

V Specification-of Letters J Fatei t. Pat l t d lu 22 2 Application filed amster, leisqseriai No. 251,604; a i

switches at any time during the progress of the selection, even though the A operator lugged into the jackof theassigned trun r l ne; The necessity for this may arise from several causes, as when shevvishes to repeat thenurnber ofthe Wanted line on her keyboard, or When she observes from the signals on her position that the selection; is not progressing. y a a Another feature of the invention thereforerelates to an arrangement which enables 'the B operator to force the release of the switches disregarding the condition of the outgoing end of the trunk line, Whether a plug; has been inserted in the jack.

Still another feature of the invention and one related to the last named is the provis on of an improved arrangement of circuits and apparatus by Which'the B operator can force the release of the switches in de pressinga co mmon koy on her position and the assignment key ndividual to the trunk line Which is otherwise used to initiate the connection of thc trunk line With a free register set. a y a a a a ii i Should the" 13 operatcrwhen desirous offorcing the release or the switches maintain the assignment key depressed for a time longer thanthe switches need for restoration to their position of rest, the trunk line may again he connected with a register set. "Still another i'eature oi the invention relating the features above-mentioned ipro videsnn arrangement ofcircuits and apparatus fornthe delaying of the forced release. untillthe 5Boperatorhas freed the assignmentkey 1 y A. further feature of uthe invention provides that apportioning means are brought into artion whereby if; the Wantedline is fonndhusythe switch yon the incoming end ofthe trunk line is held in a position sin which a hash signal transferredfrom the incoming; to; the out oing; end oithe trunk line through the medium a relay locally operated in a circuit over-ya common interc. e., a

tied up on the progress of selections. This is especially important on positions on which .orders are given to the semi-automatic B operators over order wires.

Another feature of the invention is the provisionof circuits and apparatus for the connection of a third register set on the semi- V automatic B operators position with the is given to onelof the register setstandwhen this '15 busy to the second register set, and

when this second is engaged to the third register set of theB pos1tion, whereby a register set once connected with a trunkline remains engaged, regardless of whether or not :the other registers become free, and whereby also the threeflregister sets are made busy as. long as one of them is connected with the set of number-keys.

Figure 1 shows the, connecting plug on a manual common 'battery'board of the well .knowntyp'e and the outgoing end of a trunk to a semi-automatic exchange. I Y Fig. '1 shows the, incoming end of a trunk connected to a first group selector which has access to the registers of a B operators position. v

Figs. 2 and 3 show the arrangement of three register sets, the detailed arrangement of one of the registers only being shown however, the other two registers being indicated only in so far as is necessary for the understanding of the system.

Fig. 3 also shows the keyboard for use in I connection with the three register sets Fig. 4 shows a final selector.

will be best understood from a description shown'in Figs. 2 and 3.

Fig. 3 shows a, set of counting relays for controlling selection. Fig. 4 shows a second groupselector and The system of the operation thereof. 7

When aconnection is to be extended from the manual A board' to the semi-automatic exchange, the A? operator communicates with the semi-automatic B operator over an order-wire 200 by depressing an order wire key 201, which connects'the wires 202 other telephone with the B operators telephone 301 indicated in Fig.2. The B operator responds with the number of the selected free trunk line. and depresses the assignment key 203 of this trunk line. Relay 204 is-thereby energized in a circuit over right hand contact of key 203 and sequence switch contact'205'top. The magnet of the sequence switch 206 individual to the first group selector 'on the incoming end of the trunk is thereby energized in a circuit over sequence switch contact 207 bottom, front contact of relay 204 and sequence switch contact 208 bottom. The sequence switch 206 starts from position 1 and moves under the control of its local contact 209 into its position 2, in which the searching sequence switch 251 also individual to this group selector is energized in a circuit over contact 211 top of sequence switch 206 and back contact of test relay 212.

During the time sequence switch 206 is in its position 2 and sequence switch 251 is searching for connection with a free register, the guard lamp 218 of the trunk line is connected ina circuit over sequence switch contact 217 top to an interrupter 219, and displays a flashing signal, whereas the busy lamp 216 is connected over sequence switch contact 221 bottom and is lighted. Sequence switch 251 starts from the position in which it was left on the previous call and with the help of the test relay 213 searches for a connection with a free register of the operators position. Contact 252 top of this sequence switch is closed for a short time between each position in which the sequence switch 251 can obtain a connection with a register. The semi-automatic B opelators position is provided with three register sets designated A, B, and C, the controlling sequence switches of which are diagrammatically indicated in Fig. 2. The sequence switch 251 can obtain in positions 1, 4, 7 or 10 connection with the A register in positions 2, 5, 8 or 11 with the B register, and in positions 3, 6, 9 or 12 with the C register. Privilege, as will be described, is given to the A register. When this is engaged with a trunk line the other registers of the position are isolated until the number keys have been depressed. The B register can then be taken, and during the time the A and B registers are engaged after the number keys have been depressed a second time, the C register is available. A connection once established with one register cannot be disturbed through another register becoming. free.

Assuming that the three registers are free and that the sequence switch 251 had started from position 6; before reaching position 7 the right hand high resistance winding of the test relay 213 is temporarily connected to ground over the sequence switch contact 252 top, and relay 213 is energized in a circuit over contact 214 bottom of sequence switch 206, contact 255 bottom of sequence switch 251, common wire 390, right hand winding of relay 311, Fig. 2, relay 312, contact 313 top of sequence switch 310 individual to the A register, back contact of relay 349 individual to the C register, and contact 335 of sequence switch 330 individual to the B register. The circuit closing positions of sequence switch contact 252.

are soarranged that this contact is closed in its halt positions 't'oran lnterval during and the second test relay 212 inparallel to its high resistance winding before contact 252 is opened. A busy potential is created on common wire 390 and relays 212, 311

and 312 are energized. The circuit for so quence switch 251 is opened on back contact of relay 212 and this' sequence switch is arrested in position 7 as soon as its local contact 254 is also opened. Sequence switch 206 is now energized in acircuitover sequence-switch contact 215 top and front contact of relay 212, starts from its posit1on2 and moves over position 3 into position 5, in

which the busy lamp 216 associatedwith the trunk is connected in circuit over sequence switch contact 217 bottom and the interrupter 219. The lamp 216 displays a flashlays 213 and'212 are disconnected! The guard lamp 218 is disconnected from the interrupter 219 and connectedover sequence switch contact 228 bottom with the back contact of relay 229. j

Belay 311 provides over its right hand front contact and sequence switchcontact 314 bottom a startingcircuit :torsequence switch 310 which moves from position 1 into 5. Over the left front contact oi relay 311 and sequence switch contact 315, the letthand high resistance winding oi' this relay is connected in series with its right hand winding. Relay 312 when energized provides the connection of relay 316 in series with relay 811 and in parallel to the test relays 213, 21.2. Relay 316 is thereby energized and connects over its front cone tact battery direct to the winding oi relay 312, so that the high resistance winding); of relay 311 remains still shunted by the winding: of the low resistancerelay 312, so prcventing the deenergization of the marginal test relays213 and 212, in case sequence switch contact 313 is opened before sequence switch 206 reaches its position 4. VVheu sequence switch 206 is inpositi on 4 the direct ground connected oversequence switch contact 221 causes the shortrircuiting of re lay 316, which is deenergized and leaves the left hand high resistance winding of relay 311 to maintain its energization. Sequence switch 310 in reaching position 5 tests whether thenuinber keys Ofthfi operators position are free. If this is the case relay 401, 3, is deenergized, the energization of sequence switch 310 is maintained over back contact of relay 401 conductor 481 and ing signal, indicating the connection with a register, which is now kept busy over quence switch contact 221 top." The test re;

sequence switch contact 317 top,and the sequence switch moves into position 6 in which the magnetic clutches 402 of the number keys 403 are energized in a circuit over the wipeoutkey 404 conductor 482 and: se-

quence switch contact 318 top. Seeing the flash of thebusy lamp 216, the operator depresses on the number keys the number Wanted and after one key in each row is depresseda circuit is closed for relay 401 over the right hand contacts of the depressed 10000s, 1000s, 100s", 10s and units keysand relay 401isenergized, Sequence switch 310 is energized in a circuit over iront contact of relay 401 conductor 483 and sequence switch contact 319 top. This sequence switch starts from position 6 and moves into position? in which contact 321 is closed, connectingbattery to contact 333 of sequence switch 330 sothat from this inoment theB register is made free and can be connectedwith a trunk line tor afollowing call. The left hand winding of relay 349 is thereby also energized but 1 this remains, in the present state of the circuit, without e!- tect on the C register. v

In parallel to the winding of relay401 a circuit overconductor 484 sequence switch contact 32S conductor 485 and the back contacts of the test relays 405, 406, 407, 408, 409, connects and energizes the respective magnets of the registers 411,412, 413. 414, and '11., This circuit also contains the \vindi of uncommon relay 400 which is thereby energized. The registers 411, 412,

t13,'414, 415 start to rotate from the positions in which they have been left on the previous call and during); their rotation the corresponding test relays search the delay 405 will be energized in. circuit over.

contact 416 bottom of register411 and. the left hand contactot key 1 as soon as this register reaches position 1. Register 411 is then disconnected on back contact of relay 405 and is held in posiv ion 1, After all rep;- isters have beens o arrested in positions cor responding to the depressed number keys, relay 400 is det-nergized. Sequence switch 810 is now energized in a circuit over its con tact 317 bottom conductor 486 and back coin tact of relay 400 and starts from position T. moving into position 10. as soon as sequence switch. 310 leaves position 7 and contact 318 opened, the magnetic clutches 402 are disconnected and the number keys are made free so that relay 401 also becomes deenergized. v 1

In position 10 of sequence switch310 the fundamental circuit is closed for the first group selector containing thestepping relay 322and relay 204, from sequence switch contact bottom, conductor 48?- back con- The energlzation of tact ofthe zero counting relay 422, stepping relay 322, conductor 391 Sequence switch contact' 253 bottom sequence switch contact 222 top relay 2041. Both relays S22 and 204 are energized. Belay 322 provides the encult for the energization of the counting relay according to the position of the'registers 111 and 4-12. Register 111 serves only to control translation for the odd and even initial digit of the number of the desired line the capacity'ol the exchange beingassumed to be 20000 lines. Assuming that the numberjwanted was 11319, the counting relay 4241s energized in a circuit over front i'contactoi relayr322, sequence switch contact Scamp conductor &88, sequence switch contact 131 top ofregister 412', contact 117 bottom or register an, conductor 171, and back contact of relay 1-23. Relay 424 provides a holding circuit over winding of relay front contact of relay 42 1 conductor 189 and sequence switch contact 318 bottom. Relay 423 remains, however, delinergized, being sh'ort-circuited at the front contact of relay 322.

the relay 204 causes overfits front contact the operation or" se- 'quence switch 206, and this sequence switch starts from its position 5 and moves into its position 6 in whicl gthe magnet 223 of the trip spindle is energized in a circuit over sequence switch contact 224:? bot-tom and "front contact of relay 204. T he trip spindle starts to rotate and between each position a short-circuitingoi relay 822 takes place in the wellknown manner on the contact 225 top of the trip spindle over sequence switch contact 226 bottom or the sequence switch 206. As soon as the stepping relay 322 is decontact of relay 4:22, and sequence switch 310 is energized in'a circuit over front contact of relay 4126 conductor 4:90 and sequence switclicontact 319bottom. Sequence switch 310 starts from its" position 10'and moves into its position 12. In leaving position 10 the ground is disconnected sequence switch contact 323 bottom and the fundamentalcircuit is again prepared this time over the top of this-sequence switch contact 323, conductor 393'and sequence switch con tact 256; The holding circuit of the counting relays is opened on sequence switch contact 318 so that the current is first reduced through introduction of resistance 32?, and the counting relays are then deenergized.

The purpose of resistance 32? is to reduce the sparking on this sequence switch contact.

As soon as the short-circuiting contact on the trip spindle is also opened relay 201 is decner 'ized and sequence switch 206 cnergize'rl in a circuit over sequence switch contact 215 bottom, back contact of relay 201 and'sequence switch contact 20? bottom. Sequence switch 206 starts from position 6 and mores into position 7 in which the test relay 213 is connected with the tcst brush 227 of the first group selector. Relay 201 is again energized in a circuit oycr contact 226 top oi sequence switch 206, contact 257 ct sequence switch 251. conductor 302 so quence switch contact 32l of sequence switch 310 and front contact of relay 311. In position 7 of sequence switch 206 a circuit is also cl sed over back contact of relay 212 and rcquencc switch contact 211 bottom to the power magnet 2%0 of the brush carriage, and

-the carriage is moved in the well known manner with its appropriate brushes sclectcd and released by the set position of the trip spindle making contact with the terminals of the selected terminal row. llclay .213 searches for a tree trunk line to a second group selector and upon finding such a line its ht hand winding is energized in a circuit, over sequence switch contact 205 bottom and over sequence switch contact 214: top. test brush 22?. contact 501 oi sequence switch 510 individual to the free second group sclectorand right hand winding of relay .302.

The left hand low resistance winding of elay 213 is brought into circuit over its "from: contact together with relay 212 in parallel to the high resistance winding of relay 213. lhe test terminal of the second group selector is so made busy and relays 212 and 502 are energized. Sequence switch 206 is now energized in a circuit over front contact of relay 212 and sequence switch contact 215 top. The holding mannet 215 of the brush carriage is thereby also energized in a pa allcl circuit containing sequence switch contact 2 1 1 bottom. The brush carriage is arrested and the scqucncc switch 206 starts fron position 7 and moves over position 8 into position 0 by means of a circuit closed through upper contact 215 and the front contact of relay 212. The

progressot the selection is now made dcpendent on whether the operator has plugged into the jack on the outgoing end of the trunk. As long as this is not the case the guard lamp 218 remains lighted in a circuit over sequence switch contact 228 bottom and back contact of relay 229.

If or after the plug is inserted relay 230 on the outgoing end of the trunk line and supervisory relay 231 in the cord of the Ar operators position are energized in a circuit over the sleeve of the comiecting plug, both windings of relay 232 are brought over the front contacts of relay 230, in connection with both wires of the trunk line 270. Release relay 233 which is connected with its high and low resistance windings together with a retardation coil 234 in bridge to the incoming end of the trunk is now energized in a metallic circuit, and causes over its front contact the energization in a local circuit of relay 229. The sequence switch 206 having reached position 9 is now energized in a circuit, over front contact of relay 229, back contact of supervisory relay 235, se quence switch contact 210 bottom, and moves into position 10. The fundamental circuit is new extended over sequence switch contacts 236 and 237bottomand the brushes 238 and 239 of the first group selector to the fundamental circuit of the second group selector which is closed on sequence switch contact 503 bottom to relay 504 and on sequence switch contact 505 bottom to ground. Relays 504 and 322 are energized. The circuit for the counting relays is again closed over front contact of relay 322, sequence switch contact 363 bottom, conductor 491 contact 441 bottom of register 413, contact 432 bottom of register 412, wire 473, back contact of relay 427 to winding of counting relay 428. Relay 428 is energized and provides a holding circuit for its winding over its front contact and winding of relay 427 Relay 504 when energized provides a circuit over its front contact and sequence switch contact 506 top for the energization of sequence switch 510 which starts from position 1 and under thecontrol of its local contact 511 moves into position 2 in which the left hand high resistance winding of relay 502 is brought in the circuitof the test terminal 227 after sequence switch contact 501 is opened. The magnet 520 of the trip spindle is in this position ofuthe sequence switch energized in a circuit over the sequence switch contact 507 bottom and front contact of relay 504. The trip spindle moves and provides again the short-circuitings on the fundamental circuit over its contact 508 top and sequence switch contact 509 top. As soon as stepping relay 322 is de'e'nergized relay 427 becomes energized, disconnects the winding of relay 428 and connects wire 473 v with winding of relay 429. The counting relays are thus energizedin successionuntil on the last short-circuiting of the trip spindle relays 422 and 426 are energized and the fundamental circuit is again opened. Sequence switch 310 is again energized in the circuit described and moves fromposition 12 into position 14. After leaving position 12 the holding circuit for the counting relays is again temporarily opened on sequence switch contacts 318 and 326 and the counting relays are denergrzed; The fundamental circuit is maintained opened on sequence switch contact 323 until sequence switch 310 reaches position 14. The duration of this opening of the fundamental circuit onthe register is so selected that after the short-circuiting contact 011 the trip spindle of the second group selector, is opened, relay-504 is deenergized, sequence switch 510 is started from position 2 in a circuit over back contact of relay 504 and sequence switch contact 514 bottom, and the fundamental circuit is opened on contacts 503 and 505 of the sequence switch 510 be fore the circuit is again closed on the reg ister.

Sequence switch 510 moves into position 3 in which the power magnet 530 of the brush carriage is energized in a circuit over back contact of test relay 5121 and sequence switch contact 515, and the brushes of thecarriage are moved along the terminals of the filial selector in the terminal row which corresponds with the position of the trip spindle, whereby relay .513 which is connected with the test brush 527 tests fora freefinal selector. NVhen sucha terminal is found, the left hand high resistancewinding of relay 513 is energlzed in a circuit containing right hand front contact of relay 502, sequence switch contact 516 top, the test brush 527, contacts 540 and 541. of the sequence switch. 550 individual to the free final selector and the right hand winding of relay 542. The right hand low resistance winding of relay 513 is brought in parallel to its high resistance winding in a circuit over its front contact, sequence switch contact 517 and winding of relay 512, and the test terminal of the final is so made busy, and relays 512'and 542 are energized. .The sequence switch 510 of the second group selector is now energized in a circuit over front contact of relay 512 and sequence switch contact 514 top and, the holding magnet 525 is connected in parallel to the sequence switch over sequence switch contact 506 bottom. The brush carriage is arrested and sequence switch 510 starts from position 3 and moves over positions 4 and 5finto position 6 in which the fundamental circuit is extended to the final over the sequence switch contacts 518 and 519 and the brushes of the second group selectors 538 and 539, whereby the fundamental circuit isclosed 011 contact 543 top of sequence switch 550 to relay 544 and over sequence switch contact 545 top to ground. The stepping relay 322 and relay 544 on the final selector are energized. The

circuit for the counting relays is new again energized. a

Relay 544 causes the energization of sequence swltch 550 in a circuit over sequence switch contact 556 top and frontcontact of relay 544. The '-sequence switch 550 starts from position 1 and moves under the control of its local contact 551 into position 2 in which the trip spindle magnet 560 is energized in a circuit over sequence switch contact 557 bottom and front contact of relay 544. The tripspindle starts'and provides on its contact 558 top and over sequence switch contact 559 top, shirt-circuitings in the fundamental circuit and the counting relays are again operated in succession as hereinbefore described. After relays 422 and 426 are-again energized the fundamental circuit is again opened and sequence switch'310 is energized and moves from position'14 into position 16. The holding circuit for the countingrelays is again temporarily opened and the fundamental circuit is held opened as described until sequence switch 310 reaches position 16,

whereby the opening of the fundamental circuit 'is o'f-such duration that after the short-circuiting contact 558.011 the final is opened, relay 544 is deenergized and sequence switch 550 energized in a circuit over back contact of relay 544 and sequence switch contact 561 top, and starts from position 2, moving into position 5. The sequence switch contact 55'7- is opened before the" fundamental circuit isagain closed on the register and on; the other hand the energization of relay 544 takes place before sequence switch 550 reaches position 5, in which position "the power magnet 570 of the brush-carriage is energized in a circuit over front contact of relay 544 and sequence switch contact 562 top. The carriage moves -with the brushes along the terminal row which has been selected by the position of the trip spindle.

LVVhen thefnndamental circuit is again closed on contact 323 in position 16 of sequence switch 310, the counting circuit is again established over front contact of stepping relay' 322, sequence switch contact 325 top, conductor 493', contact 442 top,of register 413, contact 469 bottom, back contact of relay478 and winding of counting relay 479, so that relay 47 9 is energized. When the brush carriage during its rotation provides the short-circuiting on the fundamental circuit over its contact 563 top and sequence switch contact 559 top the stepping relay 322 controls in the manner described the operation" in succession of the counting relays until relays 422 and 426 are energized, when the fundamental circuit is opened and sequence switch 310 is energized, startsfrom position 16 and returns to its position of rest. In leaving position 16 the sequence switch 310 provides the opening of the holding circuit for the counting relays'fas well as the fundamental circuit, as described. In opening sequence swItch contact 315 relay 311 is deenergized and closes at its back contact a circuit enabling the sequence switch 310 to remain energized in position 18 over its contact 314 top, and to move into its position 1. The A register is now free to be used for another connection. The opening of the right hand front contact of relay 311 causes the deenergization of relay 204 which provides over its back contact a circuit for sequence switch 206, as described, so that this sequence switch starts from position 10 and moves into position 12 in which relay 204 is again energized in a circuit over sequence switch contact 210 top, back contact of relay 235 and front contact of relay 229. The busy lamp 216 is now disconnected from the interrupter 219 and connected over sequence switch contact 221 to ground displaying a busy signal during the connection.

Returning to the operation of the final selector, its relay 544 becomes decnergized after the opening of the fundamental circuit as soon as contact 563 top of the brush carriage is opened. Sequence switch 550 is again energized in the circuit over back contact of relay 544, as described. In parallel to the sequence switch the holding magnet 580 is connected over sequence switch contact 581. The brush carriage is arrested on the terminals of the wanted line and the sequence switch 550 starts from position 5 'and moves into position 10. By the opening of sequence switch contacts 543 and 545 the fundamental circuit is now disconnected on the final selector. The deenergization of-relay 311 on the register is controlled on the sequence switch contact 315 of register 310 so that the fundamental circuit on the final selector is opened before sequence switch 206 reaches position 12 in which the brushes 238 and 239 are connected over the sequence switch contacts 236 and 237 respectively with the current supply bridge containing the supervisory relay 235 and retardation coil 241. \Vhen sequence switch 550 leaves position 6 the left hand high resistance winding of relay 542 is brought into the circuit of the test terminal 527 as soon as contact 541 is opened. When sequence switch 550 of the final selector passes position 8 a test is made on the wanted subscribers line through a temporary closure of sequence switch contact 564 to ground, so that if the line is free the right hand winding of the test relay 573 is energized in a circuit containing sequence switch contact 564, the test brush 567, and the cut-off relay 568 of the wanted line. The left hand low resistance winding of relay 57 3 is brought in parallel to its high resistance winding over its front contact, winding of second test relay 572 and front contact of relay 542. The test terminal of the wanted line is thus made busy, and the relays 572 and the sequence switch moves over positions 10 and 11 into position 12 in which the'ringin current supply and the ringing relay 574 are connected over sequenceswitchcontacts 575 and 576 respectively with the wanted line.

In positions 8 tell of the sequence switch 550 a resistance 577 is brought inbridgeto" the line and relay 235 is energizci'l.r*in. metallic circuit over the brushes of the first and second group selectors and theseqnence switch contacts 545 bjottoinand 578 top of the final selector. The circuit described for. relay 204i is now opened on back contact of relay 235 and the sequence switch .206 is again energized over the back contact of relay 2%. This sequence switch starts from.

position 12 and moves into its position 13;

As soon as sequence switch 550 of the fin connected and relay 235 is deenergized;

Sequence switch 206 is now energized in a circuit over its contact 210 bottom, baclrcontact ofrelay 235. and front contact of: relay 229, the sequence switch starts trom position 13 and moves into position l lin which relay 204 is again energized over back contact of relay 285 as described. When the called subscriber replies by removing the receiver from the switch hook ringing relay 574 on the final selector is energized over the called subscriber line and causes the energization oi'tsequence switch 550 in a cir cuit. over its contact 569 top and :lront contact of relay 574:. The sequence switch 550 starts-from position 12 and moves into position 13 in which the ringing" current supply is disconnected on the sequenceswitch contacts 575 and 576 and through connection with the wante clhne is made on the top of these contacts. Re-lay 235 is new again energized and relay 20-1 deenergized, caus- 111g again over itsback contact, as described, the energization ol sequence switch 5206, which starts from position 14s and mores into position 15, in which position the sequence switch remains during the conversation. The right hand high resistance windin of: relay 233 is now shortcircuited over soquence switch contact 2&2 bottoni back contact of relay 204; and sequence.switch contact 207 top. Relay 232 on the outgg'oing end of the trunlris new energized and provides on its front contact the shoirt-circuiting; of supervisory relay 231 on the cord. 'lhetime the short-eircuiting contact 563 of the brush carriage or the linalselector closed is not in all cases the same, the final selector being arrangedEOrQOO subscribes lll16S.,l3l16tGl'HllllttlS otthe oddand even hundred are separated from oneanotherand A operator.

when the brush cz'trriage inoves over this spacethe short-circuiting on contact 563 is of coniparatii ely long duration. To control-the moment when sequence switchQllG sl iall be started from position 10 an arrangement is made over acontact e l?) of the lOOs registers 4-13 and a contact tfil oi the units register 115, so that it according to the de pressed number keys the 100s register in one of its positions 1-3-5-7-9 and the units register is in its position 0, which corresponds to the first terminal in the second half oi the terminal row of a final selector, relay 311is maintained energized after sequence switch. 810 leaves position. 16 in a circuit over conductor ll-.94: contacttti ott register 4513, contact 46101: register 4'15 conductor 4-95 and sequence switch contact 318 bottom, until the sequence switch 310 leaves its position 17. The deenergization ofrelay 311 andin consequence relay 204i and the starting of the sequence switch 206 is therefore delayed for a corresponding length of time.

lt hen the conversation is finished called subscrlber replaces lllSTfiCGlVQl' on the and the hooh,' relay 235 is deiinergized and in consequence relay 20 i energized. The shortcirouit of the; high resistance winding" of fronrthe jacks, relay 233i; deenergizcd and in consequence relay Motor'magnet of sequence switch 206 is now energized. in a circuit over sequence switch. contact208 top and baclt contact of relay 229 and the sequence switch moves :lroin position 15 1nto oosition; 18. In learinn iositioni 15 the is l brushes of the first gjl'Ollp selector are isolated on sequence switch contacts 214-, 236 and. 237. relay 502 on the second group selector isdeenergized and sequence switch 51.0 is energized in a circuit over its contact 521 top andthe back contact of relay 502, and so quence switch 510 starts :lrono positionG and nioves into position 10. FIOHI position 10 said sequence switch :ul'vauces to position 17 by means ol? a circuit closed over the buck contact of relay 50 i and the lower contact 514K. l

After sequence switch 510leaves ymsition 16, the circuit over the tcstbrush 527 is opened on sequence switchcontact 517 and the relay 542 on the final selector is deiiner relay Ydeenergized the sequence switch inaintanis' ts energizatlon over sequence switch contact 561 top, and back contact of relay 1a. Sequence switch 550 moves then over position 15. Imposition 16 the energizationof this sequence switch is again maintained over its/contact 556 bottom and back'contact ofrelay 542 so that the sequence switch moves into position 18.

hen sequence switch 206 reaches position 18 the power ma net 240 of the first group I p t; q I l selector 1s again energized 1n the circuit over sequence switch contact 211 bottom and back contact of relay 212, and the brush carriage is restored to its position of rest whereby-'21s soon asthe home contact 243 is closed relay-212 is energizedin a circuit over home contact 243,'s equence switch contact 24A top and the holding magnet 2415, the brush carriage is arrested, and the sequence switch 206 is again energized in a circuit over its contact 215 top and front contact of relay 212. The sequence switch 206 moves from position 18 into position 1, sequence switch contact 221 is opened :and

lamp 216 extinguished r Whenthe sequence switch 510 of the sec- 0nd group selector reaches its position 17 the power magnet 530 is again energized in a After the home contact 523 is closed'relay 512 IS energized in a circuit over home conits contact 514 top and front contact of relay circuit over sequence switch contact 515 and back contact of relay- 512, and the brush carrlageis' restored to its positlon of rest.

tact 523and sequence switch contact 521. Thepower magnet is disconnected and the sequence switch 510 is again energized over 512. ln'parallel to the sequence switchis thereby connected'the holding magnet 525 over sequence switch contact 506 bottom. The brush carriage is arrested and the sequence switch moves from position 17 into position 18, in which the trip spindle mag 'net'520 is energized in a circuit over se-' quence switch contact 507 top and trip spindle contact 508 bottom, also relay 504 is maintained in its position energized over When the sequence switch 550 of the final selector reaches position 18 the final selector power magnet 570 is energized in a circuit over sequence switch contact 561 bottom and .b ack 'c ontact o'f relay 54A, and the brush carriage is returned to its position of rest in which the homecontact 563 bottom is closed and relay 544 is energized in'a circuit over sequence switch contact 559 bottom and thehome contact'563 of the final brush carriage. The power magnet 570 is disconnected and sequence switch is again euergized in a circuit over its contact 556 top and front contact oi relay 5&1. In parallel to the sequence switch 550 is connected the holding magnet 580 over sequence switch contact 581 bottom, the brush carriage is arrested and the sequence switch is started from position 18 and moved into position 1.

If the wanted line has been found busy and test relay 573. when the sequence switch 550 passes position 8, was not energized the sequence switch 550 is arrested in position 10 in which the power magnet 570 .is energized in a circuit over sequence switch contact 561 bottom and back contact of relay 5n, and the brush carriage is moved into the position of rest. \Vhen the home contact 563 of the brush carriagcis closed, relay is energized in the circuit over sequence switch contact bottom and over contact of? the brush carriage 563 hottom power magnet 570 is disconnected. and the sequence switch 550 and the holding magnet 580 are energized over the front contact of relay 54A and sequence switch contact 556 top. The brush carriage is arrested and sequence switch 550 is moved into position 11. Resistance 577 remains connected over sequence switch contacts and 578 in bridge to the line and relay 235 is continuously energized during the time the brush carriage is restored to its position of rest and also when the sequence switch 550 remains in position 11. The sequence switch 206 individual to the first group selector held in position 13. Relay 204: is in this position connected over sequence switch contact 222 bottom to a. common interrupter 2 16 and each time the interrupter is closed relay 20 1 is energized and the high resistance winding of relay 233 is short-circuited over sequence switch contact 207 top, front contact of relay 20 1- aud sequence switch coutaet 242 top. Relay 232 is thereby each time energized and in short-circuiting on its front contact relay 281 causes the extinguishing of the supervisory lamp on the cord. A busy flash signal is so transmitted to the A operator who informs the calling party and disconnects by withdrawing the plug from the jack. Relay 233 is thereby dei nergized and in consequence relay 220. Sequence switch 206 is energized over its contact 208 top and back contact of relay 229. starts from its position 13 and moves over its positions 14 and 15 into position 18. in which the brush carriage is restored and the second group selector is released. as has been described.

.Vi hen sequence switch 510 opens contact 517 and in consequence relay 5 12 on the final selector is deenergizcd, the sequence switch 550 is energized over its contact 556 bottom and back contact of relay 54-2 and starts from its position 11, moving over positions 12 and 13 after which it continues the release, as has been described.

If a premature release is made during the progress of selection through the withdrawal of the plug on the outgoing end of.

the trunk, rela'y 233 is deenergized and in consequence relay 229. The sequence switch 206 is energized in the circuit over back contact of 229 as described, starts from position 10 and is moved into position 18. If the premature release happens at the time the second group selector is searching for the terminals of a free final selector, a relay 502 being deenergized, after opening of contact 214:, causes the disconnection ofthe left hand high resistance winding of the test relay 513, and sequence switch 510 is energized in the circuit over its contact 521 top and back contact of relay 502 and advances olver position 3 and 4 into position 5 in which the power magnet 530 being energized over the back contact of relay 512, continuesto rotate the brush carriage without testing the terminals, until the brushes are restored to their position of rest and the home contact 523 is closed. Relay 512 is thereby energized in the circuit over the home contact 523, as has been described, the power magent 530 is disconnected and sequence switch 510, together with the holding magnet 525 is energized, the brush carriage is arrested and the sequence switch 510 is started from its position 5. In position 6 the sequence switch 510 maintains its energization over back contact of relay 502 and moves into position 17. y

The B operator is also enabled to force the release of a connection in exceptional cases,

such for example when she desires tocorrect a mistake before theselection is completed and ringing current sent to the subscribers station. To force the release the B operator depresses the assignment key 203 together with a common forced release key 360 shown in Fig. 2. Relay 247 in Fig. 1 isthereby energized in a circuit over conductor 394 and both keys mentioned and in closing its left hand contact maintains its operation also after the keys have been restored. On its right hand contact relay 247 prepares a circuit for the sequence switch 206 over se quence switch contact 248 top and the left hand contact of the assignment key. The sequence switch can therefore only start the releaseafter the assignmentkey is freed, so

that the trunk cannot be assigned a second time, which could otherwise happen if the assignment key remains depressed until the sequence switch reaches position 1. If the B operator undertakes a forced release during the time the sequence switch 206 is in position 2 and thesequence switch 251 is rotating searching for a free register with which a connection cannot be for some reason obtained, the sequence switch 206 s mr mediately advanced into position 3 over the circuit as has been described, and is held in this position until sequence switch 251 reaches its position 13. The circuit for the free register or in a position in which no register can be connected so that when sequence switch 206 later passes over positions in which connections to the contacts of sequence switch 251 are made, these cannot disturb another connection with a register.

If for the purpose of obtaining a toll connection the local connection is forcibly re leased by connecting terminals 567 tempo rarily to ground, relay 572 is deenergized and the sequence switch 550 is energized in the circuit over its contact 581 top and back contact of relay 572. The sequence switch 550 moves over position 15 into position 16 and after the sequence switch contacts 575 and 576 are opened, relay 573 is deenergized and the clearing-out signal is transferred to the A operators position as described. The sequence switch550 of the final selector remains in position 16 until the connection is released on. the A board, and when relay 542 is de'energized, as has been described, se quence switch 550 is energized in the circuit over the back contact of said relay and starts from position 16, completing the re storatibn of the final selector. p

Assuming that during the time the A reg ister is engaged on the progress of a selection the B operator depresses an assignment key ofanother trunk for the purpose of establishing a new connection, the sequence switch corresponding to sequence switch 251 would. come to rest in one of its positions 2-5-8 or 11, establishing thereby a test circuit over relay 213 of the trunk, con

tact 258. of sequence switch 251 conductor 395 andrelays 331 and 332 of the B register via contact 333 of its sequence switch 330,

contact 321 of sequence switch 310 of the A quence switch 330 has left its position l the A register if it becoimes free appears busy until sequence switch 330 reaches position 7 and. its contact 335 is closed.

If the A and B registers are engaged li o - switch 251 in Fig. 1 can stop itself in'one of the positions 369 or 12, providing that the sequence switch contact 321 of sequence switch 310 of the A register is in one of its positions 7to l8'and relay 349' is energized;

and further that the sequence switch 330 is in one of its positions T to 1.8 and itscontact 335 is "closed." The test relays 313 and 312 together with the relays 3&1 and 3&2 are thereby energized in a circuit containing contact 259 of sequence switch 251; conductor 896 contact of sequence switch 3&0 of the C register, front contact of relay 34:1 and contact 335 of sequence switch 330. In positions 2 to 6 of sequence switch 3&0 the right hand winding of relay 349 is energized in a circuit'over sequence switch contact 345 and keeps on its back contacts the test circuits for the A and B registers opened.

What claimed is: r

1. Ina telephone exchange system, a telephone line, an operators position, a plurality of automatic switches, a trunk line leading from said position to said switches, manual switching means at the operators position for connecting said telephone line to the trunlrline, a plurality of controlling mechanisms, means for associating one of said mechanisms with said trunk line, means controlled by said mechanism for selectively 7 operating a portion of said switches to extend said trunk line, and means dependent upon the operation of said manual switching means for rendering said mechanism effective to control the selective operation of the remaining otsaidswitches to further extend said "trunk line. i

Ina telephone exchange system, a telephone line, an operators position, a plurality of automatic. switches, a trunk line leading from said position o said switches,

, a plug and jack switch at'the operators positio'n for connecting said telephone line to said trunk line, a. pluralityot COIltlOlllHg; mechanisms, means for associating one of said mechanisms with said trunk line, means controlled by said mechanism for selectively operating a portion of said switches to extend said trunk line, and means dependent upon the insertion of said plug in the jack for rendering said mechanism efiective to control the selectlve operatlon of the remaining of said switches to further extend said trunk line. v

3.111 a telephone exchange system, a telephone' line, an operators position, a plurality of automatic switches, a trunk line leading from said position to said switches,

ajplug' and jack switch at the operators position for connecting said telephone line to the trunk line, a plurality of controlling mechanisms, means for associating one of said mechanisms with said trunk line, means controlled by said mechanism for selectively operating a portion only of said switches to extend said trunk line, and means dependent upon the insertion of said plug in the jack for rendering said mechanism effective to control the selective operation of the remaining of said switches to further extend said trunk line.

t. In a telephone exchange system, a telephone line, an operators position, a plurality of automatic switches, a trunk line leading from said position to said switches, a plug and jack switch at said position for connecting said telephone line to the trunk line, a plurality of controlling mechanisms, means for associating one of said mechanisms with said trunk line, means controlled by said mechanism for selectively operating a portion of said switches to extend said trunk line independently of the insertion of said plug in the jack. and means dependent upon the insertion of said plug in the jack for rendering said mechanism effective to control the selective operation of the remaining of said switches to further extend the said trunk line.

5. In a telephone exchange system. a tale phone line, an A operators position, a plurality of automatic switches. a trunk line leading "from said position to said switches. a manual switching means at the operators position for connecting said telephone line to said trunk line, a B operators position, a plurality of controlling mechanisms at said last position, means controlled by the B operator for associating one of said mechanisms with said trunk, means controlled by said mechanism for selectively operating a portion only of said switches to extend said trunk line. and means dependent upon the operation of said manual switching means for rendering said mechanism cfi cclivo to control the selective operation, of: the remaining of said switches to further extend said trunk line.

6. In a telephone exchange system, a telephone line, an operators position. a plurality of automatic switches, a trunk line leading from said position to said switchcs, a plug and jack switch at the operator's position for connecting said telephone line to said trunk, a plurality of: controlling mechanisms, means -tor associating an idle one of said mechanisms with said trunk. mcaus controlled by said mechanism for selectively operating a portion of said switches to extend said trunk, and means dependent upon the insertion of said plug in the jack for enabling said mechanism to control the selective operation of the remaining of said switches to further extend said trunk. said last named means serving to cause the release of said switches when said plug is removed from the jack,

Tln a telephone exchange system, a line, an A operators position, a plurality of auto-- matic switches, a trunk leading from said position to said switches, a plug and jack switch at the operators position for conneoting said line to said trunk, a B operators position, a plurality of controlling mechanisms at the B operators position, means controlled by the B operator for associating one of said mechanisms with said trunk, means controlledby said mechanism for selectively operating a portion of said switches to extend said trunk, means dependent upon the insertion of said plug in the jack for enabling said mechanism to control the selective operation of the remaining of said switches to further extend said trunlr, said last named means serving to cause the release of said switches when said plug is removed from the jack, and means controlled by the B operator for forcing; the

release oi said switches regardless of the condition of the plug and jack switch.

8. ln a telephone exchange system, a line, an it operatofls position, a plurality of automatic switches, a trunk leading from said position tosaid switches, a plug and jack switch at the operators position or connecting said line to said trunk, a B operators position, a plurality of controlling mechanisms at the B operators position, an assigmnent key controlled by the B operator for associating one of said mechanisms with said trunk, means controlled by such meol1anism for selectively operating a portion of said switches to extend said trunk, means dependent upon the insertion of said plug in the jack for enabling said mechanism to control the selective operation of the remaiuing of said switches to further extend said trunk, said last named means serving to cause the releaseof said switches when said plug is removed from the jack, and means responsive to the operation of said assignment key for forcing the release of s: id switches regardlessot the condition of the plug and jack switch.

5). ln a telephone exchange system, a line, an it. operators position, a B operators po* sition, a. plurality of trunks leading from the i l operators position to the B operatoide position, a plug and jack switch at the ./-i operators position for connecting said line to one of said. trunks, a plurality of auto nia'tic switches, a plurality oi. controlling mechanisms at the B operators position, assignment keys each individual to one of said trunks l or associating said mechanisms with said trunks, means controlled by a selected mechanism for selectively operating a portion of said switches to extend said trunks, means dependent upon the insertion oi. said plug; in the jack for enabling such mechanism to control. the selective operation of the remaining of said switches to further extend said trunks, said last named means serving to cause the release of said switches when said plug is removed from the jack, a release lrey common to said plurality of trunks, and means responsive to the actuation of said release key and one of said assignment keys for releasing said switches regardless of the condition of the plug and jack switch.

10. In a telephone exchange system, a line, an A operators position, a B operators position, a plurality of trunks leading from the A operators position to the B operators position, a plug and jack switch at the A operators position for connecting said line to one of said trunks, a plurality oi automatic. switches, a plurality of controlling mechanisms at the B operators position, assignment keys each individual to one of said trunks for associating said mechanisms with said trunks, means controlled by such mechanism for selectively operating a portion or":

said switches to extend said trunk, means dependent upon the insertion of said plug in the jack for enabling such mechanism to control the selective operation of the remaining of said switches to further extend said trunk, said last named means serving to cause the release of said switches when said plug is removed from the jack, a releasing key common to said plurality of trunks, and means controlled by the actuation of said release key and one of said assignment keys for releasing said switches regardless of the condition of the plug and jack switch, said last mentioned means being effective to cause release of said switches only after the assignment key has been depressed and been released.

ll. In a telephone exchange system, a telephone line, an operators position, an an tomatic switch, a trunk leading from the operators position to said switch, a manual switch at the operators position for connecting said telephone line to said trunk, a plurality oi. controlling mechanisms, means for associating one of said mechanisms with said trunk, means controlled. by said mechanism or selectively operating said switch to extend sa i d trunk, other automatic switches,

a called line, means dependent upon the operation of said manual switch for rendering said mechanism effective to control the selective operation. of said other automatic switches to extend said trunk to the called line, a signal at the operators position, and means for ruminating said signal when the called line is found busy.

1.2, In a telephone exchange system, a telephone line, an operators position, an automatic switch, an auxiliary switch having successive positions for controlling said antomatic switch, a trunk leading from the operators position to said automatic switch, a manual switch at the operators position for connecting said telephone line to said V 1 trunk, a plurality of controlling mechanisms,

means for associating one otsaid mechanisms with said trunk, means controlled by said mechanism for selectively operating said automatic switch to extend said trunk, other automatic switches, a called line, means dependent upon the operation of said manual switch for rendering said mechanism effective to control the selective operation of said other automatic switches to extend said trunk to the called line, a signal at the operators position, means for stopping said auxiliary switch in a signaling position when the called line is found busy, and means for intermittently operating said signal when said auxiliary switch is in its signaling position.

13. In a telephone exchange system, a telephone line, an A operators position, a B operators position, a trunk leading from one position to the other, a plug and jack switch at the A. operators position for connecting said line to said trunk, a plurality of automatic switches, three register sets at the B operators position, a set of number keys, means for associating an idle register set with said trunk, means for associating the number keys with said register set, means controlled by said register set for selectively operating a portion of said switches to extend said trunk, and means dependent upon the insertion of said plug in the jack for rendering said register set effective to control the operation of the remaining of said selective switches to further extend said trunk, said register sets being so arranged that the first set is always taken for use when idle, the second set being taken only when the first set is busy and the third set being taken only when the first and second sets are busy, said register sets being further arranged such that none are available for use while any one is associated with said key set.

In witness whereof, I hereunto subscribe my name this 11th day of July A. D., 1918.

LIPA POLINKOVVSKY. 

